/Fill command doesn't work with the [Nether Portal]

• Details:
  Try opening Minecraft then try creating an infinite or a flat world then try writing in the commands [/Fill ~-2 ~ ~ ~-1 ~3 ~ Portal] Don't write [/Fill ~-2 ~ ~ ~-1 ~3 ~ End_Portal] , Then you will find after entering the command that it doesn't work and it fills air instead of the Nether portal.

• How to reproduce:
  By Writing [/Fill ~-2 ~ ~ ~-1 ~3 ~ Portal] The Command should works and the command should fills Portal not air.

Please fix that fast as you can and I mean in that issue the Nether Portal not the End Portal and I hope you understand my issue sorry for duplicate my issue because you didn't understand my first issue so I create a new one and this time this issue elaborated and I hope you will fix that issue early and here I attached some pictures of the issue.